WYSIWYG graphics editing
Why use an image editor when you can create a favicon using Vim and have WYSIWYG editing? This tip shows a Vim script to generate a portable pixmap format (PPM) text file that can be used to create an icon using a tool such as Netpbm. In addition, syntax commands are provided that highlight the source text file to give WYSIWYG editing (the screen shows how the icon will appear while the text is edited). Procedure As a simple example, an icon for a Swedish flag will be created. Make a file called flag.txt containing the following (the letters following "data" define the colors, other lines are ignored; B = blue and Y = yellow): Sample data for a 16x10 flag of Sweden. data B B B B B Y Y B B B B B B B B B data B B B B B Y Y B B B B B B B B B data B B B B B Y Y B B B B B B B B B data B B B B B Y Y B B B B B B B B B data Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y data Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y data B B B B B Y Y B B B B B B B B B data B B B B B Y Y B B B B B B B B B data B B B B B Y Y B B B B B B B B B data B B B B B Y Y B B B B B B B B B Make a file called append-colors.vim containing this Vim script: " Basic colors from $VIMRUNTIME/rgb.txt let colors = { \ 'k' : '0 0 0', \ 'b' : '0 0 139', \ 'g' : '0 100 0', \ 'c' : '0 139 139', \ 'r' : '139 0 0', \ 'm' : '139 0 139', \ 'y' : '165 42 42', \ 'w' : '211 211 211', \ 'K' : '169 169 169', \ 'B' : '0 0 255', \ 'G' : '0 255 0', \ 'C' : '0 255 255', \ 'R' : '255 0 0', \ 'M' : '255 0 255', \ 'Y' : '255 255 0', \ 'W' : '255 255 255'} " Append lines to current buffer consisting of header (three lines): " 'P3' = PPM (full color; numbers in ASCII decimal) " width height (two numbers) " color_depth (one number) " then lines from translating each input letter to its color triple. " We translate only the letters that follow "data" at the start of a line. " Width = number of letters in first data item; height = number data items. function! AppendColors(data_file) abort let data = readfile(a:data_file) call filter(data, 'v:val=~#''^data\s') call map(data, 'split(v:val)1:') let width_height = printf('%d %d', len(data0), len(data)) call append(line('$'), width_height, '255') for columns in data call map(columns, 'g:colorsv:val') call append(line('$'), columns) endfor endfunction command! -nargs=1 -complete=file AppendColors call AppendColors() In Vim, enter the following commands to generate the output file: :so append-colors.vim :new :AppendColors flag.txt :w flag.ppm The above commands creates file flag.ppm by translating the letters in flag.txt to the color code numbers defined in the colors dictionary in the script. The script reads the file into a list called data, then filters the list, keeping only the lines that start with "data" followed by a space or a tab character. Each element in the list (a data line) is then split into a list of whitespace-separated words, but the first word ("data") is omitted. The width and height of the icon are then determined from the number of columns and rows in the data. Then the ppm output data is appended to the current buffer. With the Netpbm tools installed, you can create an icon file (say flag.ico) using: ppmtowinicon -output=flag.ico flag.ppm WYSIWYG editing Edit file flag.txt and enter the following commands: :syntax clear :syntax match Yellow " Y" :syntax match Blue " B" :highlight Yellow guibg=#FFFF00 guifg=#FFFF00 :highlight Blue guibg=#006FFD guifg=#006FFD That will highlight " Y" (space then Y) in yellow, and " B" (space then B) in blue. The colors are solid (foreground = background). An easy way to enter the commands would be to save the above lines in file flag-syntax.vim, then edit flag.txt and enter the command: :so flag-syntax.vim To clear the highlighting, enter: :syntax clear WYSIWYG editing with full-featured syntax file An alternative to the above simple syntax commands would be to source the following syntax script while editing flag.txt: if version < 600 syntax clear elseif exists('b:current_syntax') finish endif runtime! syntax/sh.vim unlet b:current_syntax syn region ppmData \ matchgroup=ppmKeyword \ keepend \ start=/^data\>/ \ end=/$/ \ contains=ppmBlack,ppmDarkblue,ppmDarkgreen,ppmDarkcyan,ppmDarkred,ppmDarkmagenta, \ppmBrown,ppmLightgrey,ppmDarkgrey,ppmBlue,ppmGreen,ppmCyan,ppmRed,ppmMagenta, \ppmYellow,ppmWhite syn match ppmBlack /\C k/ contained syn match ppmDarkblue /\C b/ contained syn match ppmDarkgreen /\C g/ contained syn match ppmDarkcyan /\C c/ contained syn match ppmDarkred /\C r/ contained syn match ppmDarkmagenta /\C m/ contained syn match ppmBrown /\C y/ contained syn match ppmLightgrey /\C w/ contained syn match ppmDarkgrey /\C K/ contained syn match ppmBlue /\C B/ contained syn match ppmGreen /\C G/ contained syn match ppmRed /\C R/ contained syn match ppmMagenta /\C M/ contained syn match ppmYellow /\C Y/ contained syn match ppmWhite /\C W/ contained if version >= 508 || !exists('did_ppm_syntax_inits') if version < 508 let did_ppm_syntax_inits = 1 command -nargs=+ HiSet hi else command -nargs=+ HiSet hi def endif HiSet ppmBlack ctermbg=Black ctermfg=LightGrey guibg=black guifg=white HiSet ppmDarkblue ctermbg=DarkBlue ctermfg=LightGrey guibg=darkblue guifg=white HiSet ppmDarkGreen ctermbg=DarkGreen ctermfg=LightGrey guibg=darkgreen guifg=white HiSet ppmDarkCyan ctermbg=DarkCyan ctermfg=LightGrey guibg=darkcyan guifg=white HiSet ppmDarkRed ctermbg=DarkRed ctermfg=LightGrey guibg=darkred guifg=white HiSet ppmDarkmagenta ctermbg=DarkMagenta ctermfg=LightGrey guibg=darkmagenta guifg=white HiSet ppmBrown ctermbg=Brown ctermfg=LightGrey guibg=brown guifg=white HiSet ppmLightgrey ctermbg=LightGrey ctermfg=Black guibg=lightgrey guifg=black HiSet ppmDarkgrey ctermbg=DarkGrey ctermfg=White guibg=darkgrey guifg=white HiSet ppmBlue ctermbg=Blue ctermfg=White guibg=blue guifg=white HiSet ppmCyan ctermbg=Cyan ctermfg=DarkGrey guibg=cyan guifg=white HiSet ppmRed ctermbg=Red ctermfg=White guibg=red guifg=black HiSet ppmMagenta ctermbg=Magenta ctermfg=White guibg=magenta guifg=black HiSet ppmYellow ctermbg=Yellow ctermfg=DarkGrey guibg=yellow guifg=black HiSet ppmWhite ctermbg=White ctermfg=DarkGrey guibg=white guifg=black HiSet link ppmKeyword Keyword delcommand HiSet endif let b:current_syntax = "ppm" See also *Larger example using a bash script, with screen shots Comments